Amplifier PZT Type WR-75

Written by Grzegorz Makarewicz (gsmok), Warsaw, This email address is being protected from spambots. You need JavaScript enabled to view it..

The amplifier, which I would like topresentwas producedin 1962 in Warsaw, Poland. The physical evidence can be seen below in a form of themetal plateriveted to the housing.

Amongst my old tubeamplifiers this one is characterized by auniqueweight.It is solarge and bulky that thePolish Post Officerefused tosendit to mein one package.Willy-nillybefore shipment it had to bedisassembledand placedin twopackages.The choke was removed from the amplifier and along with the removable part of the metal casing was sent in a separateshipment.After this operation, some peaces of paper markers on electric wires remained in the amplifier interior- whatis mentioned inthe following description..

A metal casing is painted of so called "hammer lacquer". On all knobs someone (read: vandal) painted lines, probablyto helpassessthe location ofthe slidersof potentiometers. I tried toremove these "artisticextras" butI could not. After many years the paint is hardas steel-itdoes not takeanysolvent, and mechanicalremovalcan causedamage to the knobs' surface - so I decided not to remowe them for the time being.

The amplifier's housingis in goodcondition.First of all,it is notbent orpressed in. Unfortunatelyittooksomecorrosion.Here andthere appeared some paint chips.This is especially trueinplaces whereornamentsare attached. This can be seenin the photo below.

Manufacturerof the amplifiermounted two tastefulretractablehandles.Theirfunctionality is, however, problematic.Handlesare very short andtheenormousweight ofthe amplifiereffectively prevents to use them.

On the backin addition tothe wall outlet,input and output jacks there is a surprise- a set ofsocketsenabling measurements of voltagesand currents.

Here are fuses andsockets for connectingthe speaker.

Old type mains socket and a set oftest sockets.

Socketsfor connectinga signal source.

This is theamplifier interior after removing thecover.The coveritselfismadevery reliably and most importantly,is wellmatched to thechassis.Theassembly /disassembly issmooth(for me it was a verypositive surprise, whenI remembered disassembling the "MELOMAN" amplifier).

View of the amplifierwith tubes procession- justwonderfull.

An additionalshotslightlyfrom above.The amplifier isalldusty.Photos were madein order to documentitsoriginal state(okay, I admit that I could not resistandpolishedone of therectifiertubes, what you can seeon the followingpictures).

Nowa discreteshotfrom behind ...

...from one side...

...and the other.

At this pointI had to stopthe amplifier testification because the Important Technical Inspector had arrived.

My cat named DeeDee was particularlyinterested inthepreamptubes.

It's timeto showsome details.Inseveralphotographs, I tried tocapture as manydetails that(hopefully) can be usefulfor anyone whois faced withthe task ofrestoringtheamplifier of the same type.